Coordination of Pentacyclohexanocucurbit[5]uril with Alkali Metal Ions and Supramolecular Self-Assembly in the Absence and Presence of Inorganic Anions

摘要

The coordination of pentacyclohexanocucurbit[5]uril (PCyHQ[5]) to alkali metal cations and the formation of supramolecular assemblies in the absence and presence of [CdCl_4]~(2-) or [ZnCl_4]~(2-) anions as inorganic structure inducers have been investigated by single-crystal X-ray diffraction analysis. Studies of the crystal structures have revealed that the [CdCl_4]~(2-) or [ZnCl_4]~(2-) anions do not form honeycomb structures owing to the presence of alkyl substituents on the surface of the outer walls of PCyHQ[5], which can seriously perturb the interaction of the anions with the outer walls. Moreover, in the presence of [ZnCl_4]~(2-) anions, the formation of a new Rb-PCyHQ[5]-based 2D six-membered "bracelet" network suggests that larger ions such as Ba2+ and even Ra2+ could form this new type of supramolecular assembly.